The present invention relates to a method for improving the performance of brake pads of a vehicle braking system.
Brake pads are generally designed for durability. However, to obtain long-life, brake pads of current brake systems employ friction materials that require a xe2x80x9cbreak-inxe2x80x9d period before the pads can provide a high level of friction. As a consequence, vehicle braking may vary between the commencement of the xe2x80x9cbreak-inxe2x80x9d period, when the brake pads are xe2x80x9cgreenxe2x80x9d, and following this period.
Inconsistent levels of friction are generally not desired by drivers. Moreover, drivers are frequently unable to xe2x80x9cbreak-inxe2x80x9d brake pads in a manner to ensure high performance. Accordingly, several means have been developed by manufacturers to overcome these problems.
One such method is to burnish the brake pads prior to their installation on the vehicle""s brake system. This method involves placing the brake pads on a rotor and brake assembly and engaging the brakes until the surface of the pads have been xe2x80x9cbroken-inxe2x80x9d.
This method is undesirable because it requires significant effort to undertake.
Another method involves scorching the surface of the friction material. A laser, flame or heated plate is used to heat the surface of the brake pad. The heat alters the surface of the pad and increases its coefficient of friction. However, this method is both expensive and labor-intensive.
Finally, a coating may be applied to the surface of the brake pad to increase the level of friction on the pad during the xe2x80x9cbreak-inxe2x80x9d period. The coating is applied by spraying the pad with particles to a predetermined thickness. The coating requires additional labor and equipment to apply.
A need therefore exists for brake pads that offer a high level of friction immediately as well as over the life of the brake pad without significant expense or manpower to create.
In a disclosed embodiment of this invention, the brake pad comprises two pad layers. The two pad layers are made of different friction material and are formed together. The first pad layer is the pad layer initially in contact with the brake rotor of a brake system while the second pad layer comes into contact with the brake rotor only after wearing of the first pad layer. The second pad layer is mounted to a brake plate, which is operatively connected to the same brake system.
The first pad layer is made of a friction material that wears at a faster rate than the friction material of the second pad layer. Without the constraint of durability, the first pad layer can be composed of material that offers a higher level of friction immediately rather than after wear or xe2x80x9cbreak-inxe2x80x9d. Organic, metallic, semi-metallic and glass materials all offer immediately higher levels of friction but wear at a faster rate than standard friction material. The first pad layer may be significantly thinner than the second pad layer.
As the first pad layer wears away, the second pad layer commences to wear or xe2x80x9cbreak-in.xe2x80x9d Because the interface between the first pad layer and the second pad layer is uneven, the pad layers will wear unevenly at their interface. As a consequence, portions of the first pad layer continue to offer initially a higher level of friction as portions of the second pad layer xe2x80x9cbreak-inxe2x80x9d gradually to offer a high level of friction. Eventually, the first pad layer wears entirely away, leaving a second pad layer already xe2x80x9cbroken-inxe2x80x9d and ready for long-lasting life.
The present invention is manufactured with very little labor or expense. No additional or specialized manufacturing equipment is required either. Accordingly, the invention provides a cost-effective and efficient means to avoid the xe2x80x9cbreak-inxe2x80x9d period required of new brakes.